Attachment for securing a stranded conductor to a rail



Nov. 26, 1940. E, A EVERETT 2322,609

'r'ncausu'r FOR mum A s'rn ED comau'c'rpn TO A RAIL iled Aug. 2, 57

V 4 I 15 L12- I fig BYEJ mar J14 Epei gggg Patented Nov. 26, 1940 UNITED STATES PATENT OFFICE ATTACHMENT FOR SECURING A STRANDED CONDUCTOR TO A RAIL Application August 2, 1987, Serial No. 156,982

3 Claims.

' 10 Another object of the invention is to provide a flexible conductor with the members of the conductor brazed solid at the end and secured in an aperture of the plug; another object of the invention is to provide a plug for driving into a hole in the rail and formed with a socket at the opposite end for the flexible conductor.

Other objects of the invention reside in the method of manufacture and in the details of construction which are more fully described in the 20 following specification, and illustrated in the accompanying drawing, in which:

Fig. 1 is a horizontal plan view of a rail bond applied to the head of the rail which is sectioned in the drawing and embodying my in- 25 vention;

Fig. 2 is a side elevation of the rail bond shown in Fig. 1;

Fig. 3 is a cross section of one form of plug, made from copper coated steel showing the con- 30 ductor attachment thereto, and Fig. 4 is a view of the plug shown in Fig. 3 taken at right angles to Fig. 3 and with the conductor removed;

Fig. 5 shows a plug with another form oi attachment for the conductor thereto, and Fig.

35 6 is a top plan view corresponding to Fig. 5;

Fig. 'l is an elevation of a plug and conductor socket, partly sectioned, and Fig. 8 is a'conductor prepared for attaching to the socket in Fig. 7 by a crimping process.

40 This invention relates to the plug type of rail bond shown in U. S. Patent 2,074,379 of March 23, 1937, filed November 7,1932, U. S. Patent 2,112,- 694 and U. S. Patent 2,180,350T The rail bond in question is usually applied to the head or ball 45 of the rail in which case it must be applied to a bottomed hole, in the rail. It may also be applied to the flange of the rail where there is suificient space for this purpose outside of the 50 splice bar. The invention, however, is shown tric continuity between the rails.

to the web of the rail in which case the hole is usually drilled completely through the rail.

In practice it is found that when a plug is provided with a conical end to correspond with the conical end of the bottomed rail hole that the 5 plug will readily rebound after driving to 9. limited extent in the hole and once the plug rebounds its frictional grip on the rail is materially reduced. On the other hand, if the plug is provided with a flat nose to engage the conical 10 end of the bottomed hole, it can be driven into the hole with an increased driving force without liability to rebound, and when so driven, the nose of the plug, where it engages the rail hole, spreads or mushrooms out and increases the grip in the hole. It has been found that the plugs must be specially constructed to stand the extra driving force without becoming deformed outside the hole and this condition is liable to occur where the conductor is attached to the plug, unless itis provided for, which is one of the objects of the present invention.

In the drawing, ii is one rail and I2 is the adjoining rail which are separated by the varying joint i3 and which it is desired to bond for eleci4 is one plug and I5 is the other plug connected by the conductor it, these plugs being inserted in bottomed holes in the rail as shown. These holes are drilled with a pointed drill making the conical ended hole as indicated at ll and the plug is provide with a flat nose as indicated at i8, which causes the nose of the plug to spread in the hole as indicated at 24 when the plug is driven into the hole. The conductor I6 is attached to the plug by the ferrule 2| which is brazed or otherwise welded to the plug as indicated at 22 and is provided with a bell mouth at 23 where the conductor leads away from the fixed terminal.

The plug may be constructed as illustrated in Figs. 3 and 4, having the steel core 28 surrounded on the outside by the copper sleeve 29, made by what is known as a welded copper coating on the steel. The nose of the plug I8 is soft compared with the outer end which is hardened by a tempering process. This process may be carried on by covering the part of the plug that is to remain soft while the exposed part is heated and cooled for tempering purposes. Thetempered part of the plug may extend to the line a which is within the rail hole as the plug is driven in place.

The plug is counterbored in the side as indicated at 26 to receive the sleeve 2| and at 21 to receive the end of the flexible conductor, which may previously be brazed at the end as indicated at 33 to make a solid connection with the plug. It will be observed that the sleeve 2|, which may be made of brass or non-ferrous metal, is directly brazed to the copper sleeve 28 of the plug at 22.

It will be observed that the larger part of the plug, Fig. 3, is steel, what is known as 80% copper coated steel has been successfully used for this purpose. This term implies that the copper coating has 30% of the electric conductivity of the plug. The recess in which the sleeve II and the conductor is seated removes a comparatively small portion of the metal so thatthe plug can be driven the same as if it were solid steel and the hardening of the outer end prevents bulging or swelling of the plug as it is driven in place.

In the construction in Figs. 5 and 6 the end of the sleeve II, where it engages the plug Md is curved to correspond with the surface of the plug and is brazed thereto as indicated at 30. The plug inthis case is steel. In this construction it will be noted that the solid plug is maln tained throughout and the construction is less expensive than that shown in Fig. 3.

The conductor I6 is shown as made from stranded cable which has been found highly practical for this purpose, but if a ribbon type of conductor is to be used, the sleeve 2| must be shaped to conform to the conductor. The conductor is usually made from strands of copper or copper alloy-and it may, in some cases, be desirable to prevent excessive heat from reaching these strands, such, for instance, as would arise from brazing or welding the sleeve 2i at 22. In this case I prefer to assemble the sleeve 2! on the plug and afterwards attach the conductor, which attachment may be made mechanically in a cold state. In Fig. 'l-the sleeve 2i is brazed or welded to the plug it and the end of the conductor I8 is brazed at 33 to hold the strands together, to hold them in cylindrical form and to make this portion of the conductor solid. It is then inserted in the orifice ll of the sleeve ii and the crimping tool 35 is applied to this sleeve to crimp it around the end 33 and to make a tight mechanical connection therewith, which also forms a satisfactory electrical connection. In this operation it will be noted that the conductor 33 is heated only to the extent necessary to braze its own strands.

The plug of the terminal which is driven into the rail hole is made from copper coated steel, which is a well known commercial product and is not to be confused with electroplating, or with a non-corrosive coating of zinc or tin. Coatings of this kind are usually applied to prcvent rusting, but the copper coating of the copper weld does much more than this. It is found by experience and tests that a coating of zinc or of tin acts as a lubricant for the plug when driven in the rail hole and is a detriment to plugs that grip the rail hole by friction. Electroplating is usually applied so thin that it is partially worn oil before the plug is applied to the rail and the shear from'driving in the rail hole strips this coating entirely from the plug. It has long been recognized that tapered plugs, after therail hole is filled cannot tighten in the hole, as the excess metal merely shears oil and a coating of soft metal merely facilitates this condition.

In the copper coated construction the copper coating has substantial thickness, representing in one type, 30% of the conductivity of the iron of the. plug. This coating is not merely a sleeve or a loosely applied flux, instead it forms a weld with the iron making a solid, integral plug. This copper coating cannot be shorn away when the plug is driven in the rail hole, if a shaving is shorn oil a substantial cost remains. The copper protects the plug against rusting and it provides a large copper surface for contact with the walls of the rail hole which cannot rust in service. A copper coated plug which expands in the rail hole has a yielding copper surface in contact with the walls of the hole which makes a closer and more perfect seal than could be obtained with the iron of the plug alone. Copper for this purpose is superior to tin or zinc, if these metals could be applied in the same way, as it is more rigid and holds its shape.

Rail plugs that are made of solid copper, or copper alloy, after a time, due to temperature changes, become loose in the rail hole and require to be tightened. This condition does not arise with the type of plug in this invention as the cross-section of the copper is much less than the cross-section of the steel and there is less opportunity for shrinkage due to the diiferent metals.

Plugs of the type shown that are expanded in the rail hole are subject to very considerable pressure when driven in the hole, which pressure is exerted on the outer end of the plug and is transmitted through the cylindrical body of the plug. If the cross-section of the plug is materially reduced on one side, it has a tendency to bcnd'under the driving force. The conductor is attached by a sleeve to the side of the plug which may be brazed to the plane surface of the plug, or the plug may be recessed to a limited extent to make a seat for the end of the conductor.

The stranded cable is twisted as shown and in a uniform lay there is usually a core in the cable which is not twisted, or twisted to a less extent than the outer strands. In a tensile pull the core does not yield to the same extent as the outer twisted strands with the result that it takes most of the load and slips out of place before the other strands take their portion of the load. It is necessary, therefore, to unite the strands at the end of the cable so that they will all take a proportional part of the load as is shown by the brazed end in Fig. 8, or in Fig. 3.

The plugs are usually made from bar stock and the cable attachment is made through a sleeve brazed against the side of the plug. This sleeve is made of brass and is readily brazed against the copper coating of the plug. It is crimped or spun around the end of the cable which has been made solid by brazing. This forces the sleeve into the spaces of the cable strands in a cold assembly and the sleeve has sufficient rigidity to secure the end of the cable and to provide a satisfactory contact between the cable and the plug. 111' this construction the terminal is comparatively small and does not form an objectionable obstruction on the rail head.

The various constructions used may be applied as shown or may be used in other combinations for the purposes specified without departing from the intent and purpose of the invention.

Having thus described my invention, I claim:

the sleeve is brazed to the plug, and crimped in said sleeve in a cold state.

2. An attachment for making electrical connection to a railway rail, comprising a cylindrical plug oi copper coated steel, a sleeve having one end brazed to the'side of said plug and a flexible conductor having its end brazed solid and inserted in said sleeve after the sleeve is brazed to the plug, .said sleeve being crimped in a cold state 19 on said conductor.

3. The method of securing a stranded conductor to a plug for attaching to a railway rail,

comprising brazing one end of a sleeve to the side of the plug, brazing the strands at the end of the conductor to make a substantial solid end, inserting said end in the sleeve after the sleeve is b sed to the plug andcrimping the sleeve around the brazed end of the conductor in a cold state.

EDWARD A. EVERETT. 

